Which Democrat lost to an 80-year-old in generational battle?

Ed Markey's Democratic primary challenger, Representative Seth Moulton, 47, was the one who lost — Markey, 80, beat him decisively by more than 35 points in the Massachusetts Senate primary, undercutting Moulton's generational-change message [1, 6]. Moulton had campaigned on the need for younger leadership, but progressive figures rallied behind the incumbent instead [2, 4].